COM-Wrapper : aka "ActiveX-dll" ... easiest to use with VB5/6 or VBA,
comes with cairo as a "satellite-dll" (compiled with StdCall-callingconvention)
download-page: (a large VB-Democode-Tutorial is available there too)

Mono and .NET bindings (C# and any other CLS language) are bundled
with the Mono distribution in the Mono.Cairo library.

Cleaned up and more recent bindings for Mono/.NET can be found at NDesk (see http://git.ndesk.org/?p=cairo-sharp). Only makefiles are provided but it is simple to create a class library in Visual Studio or Monodevelop and include all the csharp files in the src directory.